The pre-season Bundesliga favourites, who ended up in 10th place after showing only occasional sparks of their brilliance, also missed out on European glory, losing in the UEFA Cup final to Ukraine's Shakhtar Donetsk last week.
With playmaker Diego joining Juventus at the end of the season, Werder are asking the Brazilian to put in one final breath-taking performance to win the cup.
Mercurial Diego has been sparkling when it really mattered, at time almost single-handedly guiding them further in their competitions.
His suspension from the UEFA Cup final was crucial, leaving Werder with no creative play in midfield and no trophy.
"This (German Cup) match is the most important one, not only during my time at Werder but the most important one of my life," Diego said.
"I am happy to be able to give something back to Werder for all their devotion. I am fully motivated for this."
Coach Thomas Schaaf, rumoured to be on his way out at the end of the season after 10 years, will have captain Frank Baumann and Sebastian Boenisch back in the squad as he bids to bring back the cup after Werder's last triumph in 2004.
BAYER COLLAPSE
Leverkusen coach Bruno Labbadia had also imagined his season differently after sitting in fifth place halfway through. But his young team's second round collapse, including eight defeats, saw them crash out of the European spots, finishing a disappointing ninth.
His job is now on the line, with defeat in the final seemingly sealing his fate after club officials called the season so far "unsatisfactory."
Leverkusen can play stunning, fast-paced football when two of the league's most dangerous strikers, Stefan Kiessling and Patrick Helmes, are in top form and Brazilian midfielder Renato Augusto orchestrates the attacks.
However, since their sensational 4-2 German Cup quarter-final win over Bayern Munich, Leverkusen have failed to replicate their good form, needing extra time to oust Mainz 05 4-1 in the last four.
Captain Simon Rolfes is fully fit to play in their third final appearance and Labbadia can only hope his strikers will be in the mood for goals to win their first German Cup since 1993.
